1. Field of the Invention
This invention relates to the field of bitstream testing devices, and in particular to a system for managing bitstreams which can be used for device testing.
2. Description of the Related Art
Electronic systems which perform data stream processing are being developed for many applications including video and audio compression such as MPEG, JPEG, and AC3, high-speed interconnection such as Fiber Channel and 1394, and digital communication such as wireless, Ethernet, V34 modems and ATM. By necessity, the development of systems for these applications includes testing and verification of system designs, and in particular, testing and verification of the system's implementation of the data stream syntax.
The data stream processing systems convert a stream of data to or from a structured sequence of data having a syntax. The syntax causes the portions of the data stream to assume meaning, i.e. the structured sequence cannot be treated as a stream of random data. Rather, the syntax is expected to be present, and structured data sequences must be used to test that data stream processing systems properly implement their functions.
A testing approach used in the past relies on a library of sample sequences which are constructed to test specific syntax rules, specific combinations of syntax rules, or performance on "typical" sequences. This approach has the drawback of requiring an enormous amount of storage space in order to provide a moderate amount of test coverage in today's increasingly sophisticated encoding and decoding algorithms. Furthermore, these libraries are difficult to produce and difficult to modify when syntax rules change. Also, simply combining libraries to test a device which incorporates multiple syntax sets does not provide adequate or efficient test coverage.